SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34d5617bc2cf1e464895f0587080b175faaec2cfd5d9cc1d2315bc33478f5a99' 
  AND token = 'afEJdwsJTO2GK8D6qSKrN7Qj5wTHMAOros+JcLIuDuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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