SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '54c9fe984764e6571695adf92146301814eac8138aec352d1aed3aea8f6df347' 
  AND token = 'xnVZTTVpGWdJJ+8RM+c/2H7i2nGDoTjzkeIPXzyjHQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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