SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb8bd933935dcaf5083ceff341ffdbdad91929eb1d2aadcf690549f97789286f' 
  AND token = 'eNDibH9WH3QRpCaFJIq8EI+wxe+VOtt/RKu/i5SVDqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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