SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0996b65d13ed44713cf0365e6fde1f073c88f9dc8683b99a5f05eee907e9562c' 
  AND token = 'xc14masG9EdMQ/64EXmxVQuxBU8RdubskiQLrohylC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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