SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cf38622a3332562eb2b0cfa8bc36622ac73ccde2d5b9c1ad44fbef651b7e3e9' 
  AND token = 'atahIOdJkFqGxdN56ltg+YpP3FzyIfEpuKmlXhhAXE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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