SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2f2aa9f71a0b80cd685ddcc3bb8a39231312b35957d655588dd734fd3dd5294' 
  AND token = 'tVmIPgRckhACrNtpnxzalcx8+tuHBBPQu5jNUZSgl08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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