SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6521c3c4d182b1850a65f961ed8c1b5bbef38386cad06bcd67e38229bdb8951' 
  AND token = 'IV8KnZjB/BgAmlwoZGsPrqf+n75gvE8J3pbrSCm1r1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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