SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4d4dbbaa51c8a8b02d7937e38edaa0adee3cbf1ae760e74b1aecde7cba794b4' 
  AND token = 'I74rBBtULHvk2fH+YIkl66VaZBUmS1cXR0KE8P/+xvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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