SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c790d7012ffc82e9f4d396cdb1e10cc31d0be929ff00e7ee62edcbd88662e70' 
  AND token = 'BHy53aZWHoCu50Im+7Ua2iJcueEkgFtRkaUFy1iFHsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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