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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81dc09a81f660c7709266b899fb900ce219674614642801cd69ad2c95a072cb0' 
  AND token = '0P5d71Jpd38YTBO5ghmP+V5JoqPOxJP/VyTEqzCDFYk=' 
  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"
    }
  }
}