SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5a53e7b879a74f5ca2cc1bf11786265a96db99a00436eb854ca408acc266054' 
  AND token = '2ZQb07HiG0ard+sw6tpJ3pID4GNSSuRIjIfRRixwmw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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