SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '685ab6e4f342f9802ba2c683969aa9c29a40f6f85ad0336c80ed6dad22ddb5ab' 
  AND token = '9BFaYxGoAwBbZqMtVjHemQ5giTL11ERywAjf59u10WU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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