SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75cc0fd1087a3607c7ae599f15e0cd68e3f3ba7fb259b8285f05f38296a9a5b5' 
  AND token = 'yfG8VJjUQj75T9FJ6p3X3uYAMGDzK64Gqb9NwphrmqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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