SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85641712dabc70caf96d6b616d9cf68eab74a74543b04ec21f2bbd4dd9e99f5b' 
  AND token = 'K44E08tRa5XBT9kGckCB0Lmq2SxCHmteVFcP+EBvojE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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