SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c917e9166c21a4cd3d4060c624bb06a5177e200967e8d64543c7cdf051ac5b5' 
  AND token = 'yD7C9lOvPxQOFAHz0p5YvH99coWyfIdH6KMkdcZnzbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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