SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '250638bf1885d077f5a035da1b85f36892c66facb73ddb1b97101f57a98d4124' 
  AND token = 'jQAhdZKUyUcbN/zjNJ0D6yvaESTQSWNAloOLYRi7UwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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