SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '044d79171f39d9a1356e1bb0ba7439120392340f9cfd7d2b42cb530842de8587' 
  AND token = 'RlNd7cL0xPMVVYzaY06DSXC2hHyCMl8tQRmLqGv+A/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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