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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e55cc96a66d69acc6e7c5c17a2296dc26a5d6ef53d033854f3efdd1de9f0a154' 
  AND token = 'N9Sb5sP6Ze3gnJ2+pbSRxBMTAiQAuLgwFQ0xaKvvDa0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}