SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a46ef98888ad8076853e51117e6ad17713728bed854203bf841867093e5e6b23' 
  AND token = 'EbYYnC62qUUhzqdQerXsbpRxxYM772q6xFN4xzgHyEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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