SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bdf6b6a62021fdce665183f596ee1cf2732894485cfff931e5174f59d99a9c9' 
  AND token = 'NYaxFU+CJMOAw+fK2PIjjE8OFjR+EP/IvDdwZBBvkKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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