SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c67d3a4809df8556eb653f4a6deb951779653c1fc34889aa27ccceb75c6edd6' 
  AND token = 'sZeZD/Cb6Bvn6pIIUUero6nEl/hxikid1flEOFDJls8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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