SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57a48e85f79fa920e679ba7ebb330a285a17e7dd1eb143a49649494fedad1f65' 
  AND token = 'saRGuGy6lE6fBw9K9ve4XBG2R4zQHA6FJhVBOQMvRZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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