SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c42e4abea25a3261b43dc186d945b7d5440d9e66300e86b4637f5d78c9ae5e7' 
  AND token = 'nwr0EL/GydIJFmOWCoGxP++Nq/g3TvDZXxgxAQYgSfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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