SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dab81f9cac8178ad0aea11fe2016605d517a7c39d91a12da25febf8d3da4914a' 
  AND token = 'MAOnpvci0cfzAxUAnqIFkJBcanE/2PdcKmPREYFi8bM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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