SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c717356d207231b57da75f05cc191a1aa2e099b5502a6194e177724eafdbba9f' 
  AND token = 'C2CNdHcbgxku6hiW0luxYOCRgGK18eWDHMdcEu5gqhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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