SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6d1a2bb2571454e190c2ecb793cb96d4dafb8852d517767c570915c9bd2cc84' 
  AND token = 'erXEJV0k9d4zfCcgSPjgUqogXwwhHH70G2dnWSrkNnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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