SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84f61bd96683b8a5a1017d1810a055cb52ebf96be2724242331221a2074ed51f' 
  AND token = 'RgAvfrbeo4FL54W8Ibsw3MK7trujVwOx2KzLF7EJyy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}