SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c0be2337646c411853a37046be9d6c7545d7ed12bef4b2091b117168426bfbb' 
  AND token = 'LRIWpziicvxQwr/xCegYT0mfcu1IxCo9NbOs2CK8ZC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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