SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cae1b96901d228904ee2a7ab72c46fdd3b3fee4a3e3a19be244ac3cde7b5fed0' 
  AND token = '4YIQbjUyc/iFAxaBIImiX6cD1QaZRLUnLZtQvzNzGck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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