SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c15b96f8fe201e0bed2624a36541353782959dd06eb2c733802b4915e6269fe' 
  AND token = 'Y4OWrtNvEeHaSKzUQA5xHTFl2BHXpJ4VTRO10F5DxcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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