SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8e2936ce9148efb11d414fed24c97caa709fcb357bec87829430441821bc2a9c' 
  AND token = 'mS/jDC+1bIJiDiQoX2cvwR/ebnq4mrHvV48V9oD4hP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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