SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5253df763e6d79dc3aed8ae48a569ac1670233ad1aee487652bba56b496fab52' 
  AND token = 'sIJUrZLbrQK4WjHHDLxa6P94A/3XvYCA5LcTLlGt5BE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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