SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ff9d633c3f9db1684d44b8ad13262758dec8361e8fbef819996eb2c4fdb94ce' 
  AND token = 'WE5aXFttKS1yR905ZKGwfaq40UjP5bbf4NIPihOljuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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