SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ec721fd6949a914b3a6a375ff60425199f18b426bb5496bab7b33517839198dd' 
  AND token = 'tGeEGBLOCtzQq5ClRhfiLpOKZdmnkY35BCLU7TfoChw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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