SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adc6126a31b5c2846e3cc8e44509c851a0d4458264a96018ff30bd081db953f9' 
  AND token = 'DgL6wgwBtkEvf1a2hxHr/pPCqjOQ+PQTkxO9xPJ9DZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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