SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b7e62ed84faefa726af33c390299c8cf0450cd29f12e0423728707ecc3038e8' 
  AND token = '+WHnrkuWDt6sJf1duYpXB2P8t0xH5CUSErvahqsM2DU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00077

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}