SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33b0b500aedd7f8e46d6548d1f7977dae489fb22b55ab5e271a26e181eb7a8c4' 
  AND token = '6btBBp02gKcBWv7cQf1iHhRPlhaygnFdPnwqtDiguxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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