SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9173161eb7b1d2694ecfbc9693e688f4f88da793924c0d489c174c314f7b40f5' 
  AND token = 'vRDah2R9Ebh3EJ4GXEqqzYpng3yKoU6ALfgCX+hzDCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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