SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88cf6e0fba886c177975febbfc90a8f50ee16ef936fce548e64f1dddf088aae5' 
  AND token = 'E8m13NsPdfQcOcL1o0Ut1lZoBwRxph+/MQbWLpNvZws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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