SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '991291fad0ad42e50df890e6e163369e970bb89ebecef3bdea449f27f9316077' 
  AND token = '2saEvOXU/ELdr6ezTr7EprEeHim+0awDFd6Ys1olTEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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