SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3de9b861de1be95e926b46f511974fba6269cd9d4e68eb2f40a8dfc0799af15' 
  AND token = 'wdeSSFzkVlavjK22sRJZsIL8yZ2kYUEUqgKOZyRAxfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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