SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c18fe50601f1653ebb74241c5deca38da92ae2641ec560bdeaa92ed6936093bd' 
  AND token = 'FIMH8/ypHl+61lO1T18QrfUOzPVh+sdUToC2VB7hank=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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