SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639c2ada11b099412f4c6ff528678066568ca90226539b8527bc56b613ce6588' 
  AND token = '+Lx36VHFsaFTPZ4i/u4CZ2JvrpTvbCRkygGcWGpkSyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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