SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe83797a8034d9acfc071d56bedb9afe9efabf9d62731d4c198016602110f136' 
  AND token = 'eRwldbRkAocrSoKJuWL/2Tl389OUrSMlGD8WVaoX2g8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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