SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f2e9ea3830d0da2e44790cae0342a2463042579a97564a3695b85d595cda3e7' 
  AND token = 'lUHKck2MI2AZUF0oKVxCWCJgP+TOfidftI4fxaEWTzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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