SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '559e53185ef0bf2187070023a2ca4a5d7f2cdd12490fd0d23d5d31ec8410267d' 
  AND token = 'VZ5qjjgAQU469pizRVVYXR7BJrWhkzR1hEm76jGmqfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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