SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9c1dc9b59e3561b795dd5bc30f940d5a21ea0e4bbdc048bea681651e7e4d4dd' 
  AND token = 'eheObr7ylaeEd0YTcdIp6uTVG1dJuoOXO/jQa/fQIUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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