SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86f250e4e8489885b906e4bc26efb6f23d7cca29959099c7a52f4fe2679eae3c' 
  AND token = 'Usvr3sKM6sYHSIj5/+1A2HHmmuMqo5NZeIe4L2RGYOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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