SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c7963ee24242896c7309802cf4f79a32d56d18641a87995cfda625b1d79296c' 
  AND token = 'EJLUq6AgsajWRV7mIHR7ERM3usFUOiSnQOtGMDpswjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}