SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cf68715c3aa2e0b4d985de55594db3e85a1bd37f9b2c3ca12792a8a22330895' 
  AND token = 'CR+VQ4mjnnQ9P+pdZQQN3K6CYMw8lxFrFRn0ICkh9qw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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