SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1148757a854dad79f92bc7cba0f08f1d95b99679e7b962d751bd37c01f12789' 
  AND token = 'KzD+h4zAActiCAK0scoAfMaI/KZSWzWfVvCmO56wmdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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