SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd8d34ccebfc7734f5fb76a7965fb4bb9c62ed7450025fe7dd909b9ca01f21fb' 
  AND token = 'fA+79RqvHicooE3if2iXq5TmwIs+XAA9zHPz53rn9BA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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