SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a61a5c954e17ebd5a1039a9ea9260d84579ee5e17f6c69a73b77a8dd1078766' 
  AND token = 'cv1bkwD+biyMZjh47BZHmkzwCoBroMnFKc86VOy0H0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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