SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639a51d92753743a2e638b525cc7407120b46533a5c893d0ac21979a2480e0a9' 
  AND token = 'qHtpElqSryqsxt1Yajcyl/xsW1KmRD7XXYm+UCieOgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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