SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80b62c4a6d40c1945c3c5f200a98e5aa1749de5794948778ca16db62c3edb1ac' 
  AND token = 'rQu8TIOnK6QwXgVOZYwa4DjiDAEGxeoWa1KYfF4DV8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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