SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ad21edf762bdb7aed680bf4257e8279f27c7ad3b823fa72bf7826265786018c' 
  AND token = 'a0207YkhTPJCHkKbSzwprPOR8Y5IzXmbXwpc65VsciU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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