SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a7a8548f0d5bddc39a69d8736642895614d7128b1c28440753eabcf0bbeb000' 
  AND token = 'AVidVxmkLPSvmbuPCDwe5s6HxIKh+d/Ax9VAtOCkfBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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