SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71289a655e05b5ed37e643e7935c6057986543e06108df2a1c2347b5261f7312' 
  AND token = 'XUtjGNwjLIqimwJqgC02mTMJd3Il78mcvcT4bfYCAYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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