SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6017b493fad432c0a456b942b6303e8749c64e6819410a0d952ae3f9e4795a26' 
  AND token = '4xIifIu+Y2xc+o3zm0/kfDGuwRZIqwcvhjKA3vcvLXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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