SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '950380077dd4ea24161259341c4c23d0a11ad76388be2efd5f1606a0870ac588' 
  AND token = 'kBPrThYTyNUanX0p4Zv7CzM5AywAlpz8ix6CucLlBYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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