SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '312cda78d67c617100e42d8185b1504bfb1022690afd1dc302b5fd46c7e378bc' 
  AND token = 'lQzn1GcvwvLPgPrHmc+cPBjQZjhdFVVNz+1k5Wz4wtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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