SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b1320d5a90519e5bb497928e65dbab84f7039b856c684ed5655ce078af2b5c4' 
  AND token = 'HwY+quQXfqG9O1BhzqgLI9Wiz8qE/1aJ8LfEs1o+JzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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