SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98fd7d0c004474e8879bc96722a8550c41b5ba2338cb8ef4c1676fa2a0441476' 
  AND token = '0S0qJZypA7KRUK49GM8FVyYCv5QN0jFCjdYSJ3mZBWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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