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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4df31d7cc8b57beb414b35d2f722010ec41cf455e927c3b121df7b2291bf0c4c' 
  AND token = '3JLT1BHDwzEUO+KdvW3fFg3RZU+bs0x61jvFzuAcrzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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