SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bceaf9db678d06b5840c83697b897d2a6825f2f50975c7a8453b0a9fe754095' 
  AND token = '0aznG2BCF6ZSOUApPYJIwF05zNKAVQqplrgtm/iExYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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