SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '134265b1bcebe7d700336637f0bfb21672733d568ceea75feae2001f8481fdc0' 
  AND token = 'XtOIfCDWd06iLMYwIcc+2BAm63jZ0gAGiO+mkhNH6ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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