SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6913195c3fe34ac112e5c55715739ab4e6f484d8ab8967b32ebd3485fdd0e24c' 
  AND token = 'wW4oGnbiPqueDuO9foYA1JJvsr+13dnvyt3ZvMRDtUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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