SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32a147081877ca401108e5ee8426a8019826514dd14939611cb68feb58276df9' 
  AND token = 'XGv9VmdcWhvu8xEa5WvcUtf6iF66IFsTOLftIATI68U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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